Model Amerex 240 - 2.5 Gal. Water Pressure is the best option for emergency first response vehicles as it fights class A fires.
Class A: Wood, Paper, cloth, trash, plastics (solids that are not metals).

Model Amerex B272NM is the best option for MRI rooms as it is non-toxic and non magnetic. B272 fights class A and Class C Fires.
Class A: Wood, Paper, cloth, trash, plastics (solids that are not metals).
Class C: Electrical Fires, Energized electrical equipment fires (anything that is plugged in).